Abstract
Objective To evaluate if a change in EULAR/ACR SLE classification criteria threshold score impacts accurate classification of SLE compared to disease-based control subjects. We evaluated a range of threshold scores to determine the score that maximizes accurate classification of early SLE.
Methods We conducted a cross-sectional study comparing SLE and control patients. A EULAR/ACR criteria score was calculated using baseline information. Sensitivity, specificity, (+LR) and (-LR) likelihood ratios with 95% confidence intervals were used to evaluate operating characteristics. Threshold scores of 6-12 were evaluated in subjects with early disease (disease duration of ≤5 years). +LR above 10 and -LR below 0.1 provide evidence to rule in or rule out SLE.
Results 2764 patients (1980 SLE cases who fulfilled either the ACR or SLICC criteria, 784 controls) were included. The EULAR/ACR SLE criteria had a sensitivity 98% (95%CI 97%, 98%), specificity 99% (95%CI 98%, 100%), +LR 95.5 (95%CI 48.0, 190) and -LR 0.03 (95%CI 0.02,0.03). The criteria operate well in early disease, women, men, and in Caucasian, Black, Chinese and Filipino ethnicities. A score of 10 maximizes accurate classification of patients with early disease +LR 174.4 (95%CI 43.8, 694.6) and -LR of 0.03 (95%CI 0.02, 0.04). An increase in threshold score from 10 to 11 results in significant worsening in -LR (threshold score 10 -LR 0.03 (95%CI 0.02 - 0.03 versus threshold score 11 -LR 0.05 (95%CI 0.04 - 0.06).
Conclusion The EULAR/ACR SLE classification criteria threshold score of 10 performs well particularly in early disease and across sexes and ethnicities.
